This invention relates to a method for driving a relay and may be used in measurement instruments, particularly in integrated circuit (IC) testing apparatus. Relay matrices have been used in the prior art for IC testing apparatus and several other kinds of measurement instruments. Prior art methods for driving a relay matrix may be divided into two categories
The first category, called "wet switching mode", involves switching relays within a relay matrix when the relay matrix is connected to a power source providing voltage and electric current used for measurement. The second category, called "dry switching mode", involves switching relays when the relay matrix is not connected with a power source.
During wet switching mode, application of voltage and electric current to the relay matrix may generate "sparks" by the action of opening and closing relays. These sparks may abrade relay contacts and thereby shorten the lifetime of the relays. During dry switching mode, on the other hand no power source is connected; therefore, no sparks are generated and the attendant abrading of relay contacts does not occur. Accordingly to our experimental data, the lifetime of relays using dry switching mode was greater than the lifetime of relays in wet switching mode by an amount on the order of 100 times. However, in dry switching mode, extraneous substances and oxidized film can be formed at relay contacts which may increase contact resistance thereby increasing inaccuracy in measurement.